Upgrading AT power supply

[sydney]

A power supply question for all you experts...
I have an AT type power supply with the p1/p2
mb connectors and would like to upgrade it from
its 145 watt capacity with an unknown cond used p/s.
Currently setup is baby at with Pcchips m-766 lmrt mb and an
Astec 145w sa147-3405 p/s. The used p/s units available
are either a Liteon 230w pa-4221-3a or a Hipro 200w
hp-200pp1. As the condition of used units is unknown,
the main concern is whether I will risk blowing my m/b
or drives if one of them is faulty or would a faulty
supply just have no output ??
The Astec has a cable that plugs into the front panel
of chassis for power on, whereas the used p/s have their own
on/off switches attached on a cable...i can live with
mounting the on/off switch , but it is whether I should
try to test p/s before trying on my system that has me
wondering. I gather powering the power supplies with
no load is not the route to follow. Advice appreciated..syd

[John Prophet]

I doubt you would hurt the motherboard....just be REAL careful to make sure you get p1 and p2 on correct...withthe 2 blk wires together!! else you will blow the motherboard....dont get em reversed.

But usually when you have a bad supply it just dies on some or all voltages.....I guess its possible that if some capacitors have dried up that it could output some weird spurious power spikes etc....but I sorta doubt it.

JP

[elroy]

With an AT p/s you can start it up without being connected to the board and check some of the voltages with a volt ohm meter. At least you would have some idea what you are dealing with prior to hooking the board to it.

[Brainchild]

All the bad PSUs I have seen are just dead.There is a fuse inside that will usually blow before any damage is done.

[Dax_Brandy]

agree with elroy. have it tested offline for voltage outputs, current and working condition under loads. you wont know how far those current surges will go to the system. good luck!